Among Some Fish, Heat Stress May Be Contagious, Study Finds

A study of zebrafish embryos finds heat stress may be contagious.

A study of zebrafish embryos finds heat stress may be contagious. Lynn Ketchum / Oregon State University via Flickr

Heat stress not only afflicts fish in uncomfortably warm waters. It may also spread to other fish, a new study finds.

Scientists have long known that fish can communicate using chemical cues. Fish harassed by predators, for instance, may release chemicals that spur nearby fish to guard against attack. The new research, authors write, uncovers “a yet untested dimension of chemical communication” — heat stress.

“We found that heat-stressed zebrafish embryos release cues into the water, which then stresses other embryos that have not been exposed to heat themselves,” tweeted Katharina Wollenberg Valero, a biologist at University College Dublin and coauthor of the study.

For the study, scientists exposed zebrafish embryos, which are comfortable in temperatures around 80 degrees F (27 degrees C), to temperatures around 90 degrees F (32 degrees C). Scientists found that these heat-stressed embryos grew faster, hatched sooner, and, once hatched, moved more slowly. They also released “stress metabolites,” the chemical fallout from their simulated heat wave.

When scientists exposed unstressed embryos to these “stress metabolites,” the embryos responded as if they had also suffered through a heat wave. The embryos grew more quickly and, after they hatched, behaved more lethargically. The findings were published in the journal PNAS Nexus.


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